Cho'Gath The Terror of the Void

Active: ChoGath stomps the ground, causing the target area to quake with the animation being visible to both teams. After 0.65 seconds, spikes emerge at the location. Enemy units in the area immediately take magic damage and are knocked up for 1 second, and when they land are slowed by 60% for another 3 seconds.
Cost: 90 mana
Cooldown: 9 seconds
Range: 950
Radius: 175
Magic Damage: 80/135/190/245/305 (+1.0 per ability power)

Toggle: Whenever Chogath performs a basic attack, he will launch spikes which deal magic damage to all enemies in a line in front of him.
No cost:
Range: 500
Magic Damage: 20/35/50/65/80 (+0.3 per ability power)

Endgame items

Void Staff

+80 Ability Power
UNIQUE Passive: +35% Magic Penetration.

Rylai's Crystal Scepter

+400 Health
+100 Ability Power
UNIQUE Passive: Damaging spells and abilities apply a Movement Speed reduction to enemies based on the spell type:
Single Target: 40% reduction for 1.5 seconds.
Area of Effect: 40% reduction for 1 seconds.
Damage over Time or Multi-hit: 20% reduction for 1 seconds.
Summoned Minions: 20% reduction for 1 seconds.
(If a spell fits in more than one category, it uses the weakest slow value.)